1.
PubChem
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PubChem is a database of chemical molecules and their activities against biological assays. The system is maintained by the National Center for Biotechnology Information, a component of the National Library of Medicine, PubChem can be accessed for free through a web user interface. Millions of compound structures and descriptive datasets can be downloaded via FTP. PubChem contains substance descriptions and small molecules with fewer than 1000 atoms and 1000 bonds, more than 80 database vendors contribute to the growing PubChem database. PubChem consists of three dynamically growing primary databases, as of 28 January 2016, Compounds,82.6 million entries, contains pure and characterized chemical compounds. Substances,198 million entries, contains also mixtures, extracts, complexes, bioAssay, bioactivity results from 1.1 million high-throughput screening programs with several million values. PubChem contains its own online molecule editor with SMILES/SMARTS and InChI support that allows the import and export of all common chemical file formats to search for structures and fragments. In the text search form the database fields can be searched by adding the name in square brackets to the search term. A numeric range is represented by two separated by a colon. The search terms and field names are case-insensitive, parentheses and the logical operators AND, OR, and NOT can be used. AND is assumed if no operator is used, example,0,5000,50,10 -5,5 PubChem was released in 2004. The American Chemical Society has raised concerns about the publicly supported PubChem database and they have a strong interest in the issue since the Chemical Abstracts Service generates a large percentage of the societys revenue. To advocate their position against the PubChem database, ACS has actively lobbied the US Congress, soon after PubChems creation, the American Chemical Society lobbied U. S. Congress to restrict the operation of PubChem, which they asserted competes with their Chemical Abstracts Service

2.
ChemSpider
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ChemSpider is a database of chemicals. ChemSpider is owned by the Royal Society of Chemistry, the database contains information on more than 50 million molecules from over 500 data sources including, Each chemical is given a unique identifier, which forms part of a corresponding URL. This is an approach to develop an online chemistry database. The search can be used to widen or restrict already found results, structure searching on mobile devices can be done using free apps for iOS and for the Android. The ChemSpider database has been used in combination with text mining as the basis of document markup. The result is a system between chemistry documents and information look-up via ChemSpider into over 150 data sources. ChemSpider was acquired by the Royal Society of Chemistry in May,2009, prior to the acquisition by RSC, ChemSpider was controlled by a private corporation, ChemZoo Inc. The system was first launched in March 2007 in a release form. ChemSpider has expanded the generic support of a database to include support of the Wikipedia chemical structure collection via their WiChempedia implementation. A number of services are available online. SyntheticPages is an interactive database of synthetic chemistry procedures operated by the Royal Society of Chemistry. Users submit synthetic procedures which they have conducted themselves for publication on the site and these procedures may be original works, but they are more often based on literature reactions. Citations to the published procedure are made where appropriate. They are checked by an editor before posting. The pages do not undergo formal peer-review like a journal article. The comments are moderated by scientific editors. The intention is to collect practical experience of how to conduct useful chemical synthesis in the lab, while experimental methods published in an ordinary academic journal are listed formally and concisely, the procedures in ChemSpider SyntheticPages are given with more practical detail. Comments by submitters are included as well, other publications with comparable amounts of detail include Organic Syntheses and Inorganic Syntheses

3.
ChEMBL
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ChEMBL or ChEMBLdb is a manually curated chemical database of bioactive molecules with drug-like properties. It is maintained by the European Bioinformatics Institute, of the European Molecular Biology Laboratory, based at the Wellcome Trust Genome Campus, Hinxton, the database, originally known as StARlite, was developed by a biotechnology company called Inpharmatica Ltd. later acquired by Galapagos NV. The data was acquired for EMBL in 2008 with an award from The Wellcome Trust, resulting in the creation of the ChEMBL chemogenomics group at EMBL-EBI, the ChEMBL database contains compound bioactivity data against drug targets. Bioactivity is reported in Ki, Kd, IC50, and EC50, data can be filtered and analyzed to develop compound screening libraries for lead identification during drug discovery. ChEMBL version 2 was launched in January 2010, including 2.4 million bioassay measurements covering 622,824 compounds and this was obtained from curating over 34,000 publications across twelve medicinal chemistry journals. ChEMBLs coverage of available bioactivity data has grown to become the most comprehensive ever seen in a public database, in October 2010 ChEMBL version 8 was launched, with over 2.97 million bioassay measurements covering 636,269 compounds. ChEMBL_10 saw the addition of the PubChem confirmatory assays, in order to integrate data that is comparable to the type, ChEMBLdb can be accessed via a web interface or downloaded by File Transfer Protocol. It is formatted in a manner amenable to computerized data mining, ChEMBL is also integrated into other large-scale chemistry resources, including PubChem and the ChemSpider system of the Royal Society of Chemistry. In addition to the database, the ChEMBL group have developed tools and these include Kinase SARfari, an integrated chemogenomics workbench focussed on kinases. The system incorporates and links sequence, structure, compounds and screening data, the primary purpose of ChEMBL-NTD is to provide a freely accessible and permanent archive and distribution centre for deposited data. July 2012 saw the release of a new data service, sponsored by the Medicines for Malaria Venture. The data in this service includes compounds from the Malaria Box screening set, myChEMBL, the ChEMBL virtual machine, was released in October 2013 to allow users to access a complete and free, easy-to-install cheminformatics infrastructure. In December 2013, the operations of the SureChem patent informatics database were transferred to EMBL-EBI, in a portmanteau, SureChem was renamed SureChEMBL. 2014 saw the introduction of the new resource ADME SARfari - a tool for predicting and comparing cross-species ADME targets

4.
Chemical formula
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These are limited to a single typographic line of symbols, which may include subscripts and superscripts. A chemical formula is not a name, and it contains no words. Although a chemical formula may imply certain simple chemical structures, it is not the same as a full chemical structural formula. Chemical formulas can fully specify the structure of only the simplest of molecules and chemical substances, the simplest types of chemical formulas are called empirical formulas, which use letters and numbers indicating the numerical proportions of atoms of each type. Molecular formulas indicate the numbers of each type of atom in a molecule. For example, the formula for glucose is CH2O, while its molecular formula is C6H12O6. This is possible if the relevant bonding is easy to show in one dimension, an example is the condensed molecular/chemical formula for ethanol, which is CH3-CH2-OH or CH3CH2OH. For reasons of structural complexity, there is no condensed chemical formula that specifies glucose, chemical formulas may be used in chemical equations to describe chemical reactions and other chemical transformations, such as the dissolving of ionic compounds into solution. A chemical formula identifies each constituent element by its chemical symbol, in empirical formulas, these proportions begin with a key element and then assign numbers of atoms of the other elements in the compound, as ratios to the key element. For molecular compounds, these numbers can all be expressed as whole numbers. For example, the formula of ethanol may be written C2H6O because the molecules of ethanol all contain two carbon atoms, six hydrogen atoms, and one oxygen atom. Some types of compounds, however, cannot be written with entirely whole-number empirical formulas. An example is boron carbide, whose formula of CBn is a variable non-whole number ratio with n ranging from over 4 to more than 6.5. When the chemical compound of the consists of simple molecules. These types of formulas are known as molecular formulas and condensed formulas. A molecular formula enumerates the number of atoms to reflect those in the molecule, so that the formula for glucose is C6H12O6 rather than the glucose empirical formula. However, except for very simple substances, molecular chemical formulas lack needed structural information, for simple molecules, a condensed formula is a type of chemical formula that may fully imply a correct structural formula. For example, ethanol may be represented by the chemical formula CH3CH2OH

5.
Jmol
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Jmol is computer software for molecular modelling chemical structures in 3-dimensions. Jmol returns a 3D representation of a molecule that may be used as a teaching tool and it is written in the programming language Java, so it can run on the operating systems Windows, macOS, Linux, and Unix, if Java is installed. It is free and open-source software released under a GNU Lesser General Public License version 2.0, a standalone application and a software development kit exist that can be integrated into other Java applications, such as Bioclipse and Taverna. A popular feature is an applet that can be integrated into web pages to display molecules in a variety of ways, for example, molecules can be displayed as ball-and-stick models, space-filling models, ribbon diagrams, etc. Jmol supports a range of chemical file formats, including Protein Data Bank, Crystallographic Information File, MDL Molfile. There is also a JavaScript-only version, JSmol, that can be used on computers with no Java, the Jmol applet, among other abilities, offers an alternative to the Chime plug-in, which is no longer under active development. While Jmol has many features that Chime lacks, it does not claim to reproduce all Chime functions, most notably, Chime requires plug-in installation and Internet Explorer 6.0 or Firefox 2.0 on Microsoft Windows, or Netscape Communicator 4.8 on Mac OS9. Jmol requires Java installation and operates on a variety of platforms. For example, Jmol is fully functional in Mozilla Firefox, Internet Explorer, Opera, Google Chrome, fast and Scriptable Molecular Graphics in Web Browsers without Java3D

6.
Simplified molecular-input line-entry system
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The simplified molecular-input line-entry system is a specification in form of a line notation for describing the structure of chemical species using short ASCII strings. SMILES strings can be imported by most molecule editors for conversion back into two-dimensional drawings or three-dimensional models of the molecules, the original SMILES specification was initiated in the 1980s. It has since modified and extended. In 2007, a standard called OpenSMILES was developed in the open-source chemistry community. Other linear notations include the Wiswesser Line Notation, ROSDAL and SLN, the original SMILES specification was initiated by David Weininger at the USEPA Mid-Continent Ecology Division Laboratory in Duluth in the 1980s. The Environmental Protection Agency funded the project to develop SMILES. It has since modified and extended by others, most notably by Daylight Chemical Information Systems. In 2007, a standard called OpenSMILES was developed by the Blue Obelisk open-source chemistry community. Other linear notations include the Wiswesser Line Notation, ROSDAL and SLN, in July 2006, the IUPAC introduced the InChI as a standard for formula representation. SMILES is generally considered to have the advantage of being slightly more human-readable than InChI, the term SMILES refers to a line notation for encoding molecular structures and specific instances should strictly be called SMILES strings. However, the term SMILES is also used to refer to both a single SMILES string and a number of SMILES strings, the exact meaning is usually apparent from the context. The terms canonical and isomeric can lead to confusion when applied to SMILES. The terms describe different attributes of SMILES strings and are not mutually exclusive, typically, a number of equally valid SMILES strings can be written for a molecule. For example, CCO, OCC and CC all specify the structure of ethanol, algorithms have been developed to generate the same SMILES string for a given molecule, of the many possible strings, these algorithms choose only one of them. This SMILES is unique for each structure, although dependent on the algorithm used to generate it. These algorithms first convert the SMILES to a representation of the molecular structure. A common application of canonical SMILES is indexing and ensuring uniqueness of molecules in a database, there is currently no systematic comparison across commercial software to test if such flaws exist in those packages. SMILES notation allows the specification of configuration at tetrahedral centers, and these are structural features that cannot be specified by connectivity alone and SMILES which encode this information are termed isomeric SMILES

7.
International Chemical Identifier
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Initially developed by IUPAC and NIST from 2000 to 2005, the format and algorithms are non-proprietary. The continuing development of the standard has supported since 2010 by the not-for-profit InChI Trust. The current version is 1.04 and was released in September 2011, prior to 1.04, the software was freely available under the open source LGPL license, but it now uses a custom license called IUPAC-InChI Trust License. Not all layers have to be provided, for instance, the layer can be omitted if that type of information is not relevant to the particular application. InChIs can thus be seen as akin to a general and extremely formalized version of IUPAC names and they can express more information than the simpler SMILES notation and differ in that every structure has a unique InChI string, which is important in database applications. Information about the 3-dimensional coordinates of atoms is not represented in InChI, the InChI algorithm converts input structural information into a unique InChI identifier in a three-step process, normalization, canonicalization, and serialization. The InChIKey, sometimes referred to as a hashed InChI, is a fixed length condensed digital representation of the InChI that is not human-understandable. The InChIKey specification was released in September 2007 in order to facilitate web searches for chemical compounds and it should be noted that, unlike the InChI, the InChIKey is not unique, though collisions can be calculated to be very rare, they happen. In January 2009 the final 1.02 version of the InChI software was released and this provided a means to generate so called standard InChI, which does not allow for user selectable options in dealing with the stereochemistry and tautomeric layers of the InChI string. The standard InChIKey is then the hashed version of the standard InChI string, the standard InChI will simplify comparison of InChI strings and keys generated by different groups, and subsequently accessed via diverse sources such as databases and web resources. Every InChI starts with the string InChI= followed by the version number and this is followed by the letter S for standard InChIs. The remaining information is structured as a sequence of layers and sub-layers, the layers and sub-layers are separated by the delimiter / and start with a characteristic prefix letter. The six layers with important sublayers are, Main layer Chemical formula and this is the only sublayer that must occur in every InChI. The atoms in the formula are numbered in sequence, this sublayer describes which atoms are connected by bonds to which other ones. Describes how many hydrogen atoms are connected to each of the other atoms, the condensed,27 character standard InChIKey is a hashed version of the full standard InChI, designed to allow for easy web searches of chemical compounds. Most chemical structures on the Web up to 2007 have been represented as GIF files, the full InChI turned out to be too lengthy for easy searching, and therefore the InChIKey was developed. With all databases currently having below 50 million structures, such duplication appears unlikely at present, a recent study more extensively studies the collision rate finding that the experimental collision rate is in agreement with the theoretical expectations. Example, Morphine has the structure shown on the right, as the InChI cannot be reconstructed from the InChIKey, an InChIKey always needs to be linked to the original InChI to get back to the original structure

8.
Organic compound
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An organic compound is virtually any chemical compound that contains carbon, although a consensus definition remains elusive and likely arbitrary. Organic compounds are rare terrestrially, but of importance because all known life is based on organic compounds. The most basic petrochemicals are considered the building blocks of organic chemistry, for historical reasons discussed below, a few types of carbon-containing compounds, such as carbides, carbonates, simple oxides of carbon, and cyanides are considered inorganic. The distinction between organic and inorganic compounds, while useful in organizing the vast subject of chemistry. Organic chemistry is the science concerned with all aspects of organic compounds, Organic synthesis is the methodology of their preparation. The word organic is historical, dating to the 1st century, for many centuries, Western alchemists believed in vitalism. This is the theory that certain compounds could be synthesized only from their classical elements—earth, water, air, vitalism taught that these organic compounds were fundamentally different from the inorganic compounds that could be obtained from the elements by chemical manipulation. Vitalism survived for a while even after the rise of modern atomic theory and it first came under question in 1824, when Friedrich Wöhler synthesized oxalic acid, a compound known to occur only in living organisms, from cyanogen. A more decisive experiment was Wöhlers 1828 synthesis of urea from the inorganic salts potassium cyanate, urea had long been considered an organic compound, as it was known to occur only in the urine of living organisms. Wöhlers experiments were followed by others, in which increasingly complex organic substances were produced from inorganic ones without the involvement of any living organism. Even though vitalism has been discredited, scientific nomenclature retains the distinction between organic and inorganic compounds, still, even the broadest definition requires excluding alloys that contain carbon, including steel. The C-H definition excludes compounds that are considered organic, neither urea nor oxalic acid is organic by this definition, yet they were two key compounds in the vitalism debate. The IUPAC Blue Book on organic nomenclature specifically mentions urea and oxalic acid, other compounds lacking C-H bonds but traditionally considered organic include benzenehexol, mesoxalic acid, and carbon tetrachloride. Mellitic acid, which contains no C-H bonds, is considered an organic substance in Martian soil. The C-H bond-only rule also leads to somewhat arbitrary divisions in sets of carbon-fluorine compounds, for example, CF4 would be considered by this rule to be inorganic, whereas CF3H would be organic. Organic compounds may be classified in a variety of ways, one major distinction is between natural and synthetic compounds. Another distinction, based on the size of organic compounds, distinguishes between small molecules and polymers, natural compounds refer to those that are produced by plants or animals. Many of these are extracted from natural sources because they would be more expensive to produce artificially

9.
Methyltestosterone
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Testosterone is a medication and naturally occurring steroid hormone. It is an androgen and anabolic steroid and is used to treat male hypogonadism and it may also be used to increase athletic ability in the form of doping. It is unclear if the use of testosterone for low levels due to aging is beneficial or harmful. Testosterone can be used as a gel or patch that is applied to the skin, injection into a muscle, tablet that is placed in the cheek, common side effects from testosterone medication include acne, swelling, and breast enlargement in males. Serious side effects may include liver toxicity, heart disease, women and children who are exposed may develop virilization. It is recommended that individuals with prostate cancer not use the medication and it can cause harm to the baby if used during pregnancy or breastfeeding. Testosterone was first isolated in 1935, rates of use have increased three times in the United States between 2001 and 2011. It is on the World Health Organizations List of Essential Medicines and it is available as a generic medication. The price depends on the dose and form of the product, the primary use of testosterone is the treatment of males with too little or no natural testosterone production, also termed hypogonadism or hypoandrogenism. This treatment is referred to as hormone replacement therapy, or alternatively and it is used to maintain serum testosterone levels in the normal male range. Decline of testosterone production with age has led to interest in testosterone supplementation, Testosterone deficiency is an abnormally low testosterone production. It may occur because of testicular dysfunction or hypothalamic-pituitary dysfunction and may be congenital or acquired, Testosterone levels may decline gradually with age. The United States Food and Drug Administration stated in 2015 that neither the nor the safety of testosterone supplement have been established for low testosterone levels due to aging. The FDA has required that labels on testosterone include warnings about increased risk of heart attacks, Testosterone supplementation is effective in the short term for hypoactive sexual desire disorder. However, its long term safety is unclear, treating low androgen levels with testosterone is not generally recommended in women when it is due to hypopituitarism, adrenal insufficiency, or following surgical removal of the ovaries. It is also not usually recommended for improving cognition, the risk of heart disease, Testosterone is used as a form of doping among athletes in order to improve performance. Testosterone is classified as an agent and is on the World Anti-Doping Agency List of Prohibited Substances. Anabolic-androgenic steroids, including testosterone and its esters, have also taken to enhance muscle development, strength

10.
Parent structure
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Parent structures bearing one or more functional groups that are not specifically denoted by a suffix are called functional parents. Names of parent structures are used in IUPAC nomenclature as basis for systematic names, a parent hydride is a parent structure with one or more hydrogen atoms. Parent hydrides have a defined standard population of atoms attached to a skeletal structure. Parent hydrides are used extensively in organic nomenclature, but are used in inorganic chemistry. To construct a systematic name, affixes are attached to the parent name, which denote substituents that replace hydrogen

11.
Norboletone
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Norboletone, or norbolethone, is an anabolic steroid that was never marketed. It subsequently showed up in tests on athletes in competition in the early 2000s. Norboletone was found to have brought to the market by the chemist Patrick Arnold, of the Bay Area Laboratory Co-operative. In 2002, Don Catlin, the founder and then-director of the UCLA Olympic Analytical Lab, in the same year, U. S. bicycle racer Tammy Thomas was caught using it and was banned from her sport. The following year, Catlin identified and developed a test for tetrahydrogestrinone, norboletone is on the World Anti-Doping Agencys list of prohibited substances, and is therefore banned from use in most major sports

12.
Tetrahydrogestrinone
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Tetrahydrogestrinone, often referred to as The Clear, is an anabolic steroid developed by Patrick Arnold. It has affinity to the receptor and the progesterone receptor. It was used by a number of high-profile athletes such as Marion Jones, tetrahydrogestrinone was developed completely in secret by Arnold as a designer drug, on the basis that doping testers would be unlikely to detect a totally new compound. In 2003, whistleblower Trevor Graham passed a spent syringe containing an amount of the drug to the United States Anti-Doping Agency. This was then transferred to the group of pharmacologist Don Catlin. Tetrahydrogestrinone has never fully tested for safety and has never entered legitimate medical use. A synthesis was devised to ensure a source of material for comparison and it was scheduled by the Food, concerns have also been raised about its potential use in animals such as in horse-racing. It has been found to bind to the receptor with similar affinity to dihydrotestosterone. According to Patrick Arnold, due to the potency, he never had to supply significant quantities to BALCO. When THG reaches the nucleus of a cell, it binds to the receptor at the ligand-binding pocket. Here it changes the expression of a variety of genes, turning on several anabolic and androgenic functions and it is the ligand’s structure which determines the number of interactions that can take place with the human androgen receptor ligand-binding domain. Even minor modifications in the structure have a great impact on the strength of the interactions this ligand has with the androgen receptor. THG, possessing a high affinity, establishes more van der Waals contacts with the receptor than with other steroids. It is this higher affinity and specific geometry of THG which makes these interactions with the androgen receptor so strong, resulting in THG’s potency. Side effects from prolonged use are likely to include infertility in men and women, as well as other steroid side effects such as acne and hirsutism. It has also used by formerly banned British athlete Dwain Chambers. THG was developed by Patrick Arnold for the Bay Area Laboratory Co-operative, the company manufactured the drug through palladium-charcoal catalyzed hydrogenation from gestrinone, a substance used in gynecology for treatment of endometriosis. In 2003, U. S. sprint coach Trevor Graham delivered a syringe containing traces of THG to the United States Anti-Doping Agency

13.
Structural analog
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It can differ in one or more atoms, functional groups, or substructures, which are replaced with other atoms, groups, or substructures. A structural analog can be imagined to be formed, at least theoretically, despite a high chemical similarity, structural analogs are not necessarily functional analogs and can have very different physical, chemical, biochemical, or pharmacological properties. Chemical analogues of illegal drugs are developed and sold in order to circumvent laws, such substances are often called designer drugs. Because of this, the United States passed the Federal Analog Act in 1986 and this bill banned the production of any chemical analogue of a Schedule I or Schedule II substance that has substantially similar pharmacological effects, with the intent of human consumption

14.
Testosterone propionate
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Testosterone propionate, or testosterone propanoate, also known as propionyltestosterone, is an androgen and anabolic steroid and a testosterone ester. Testosterone esters were synthesized for the first time in 1936, and were found to have greatly improved potency relative to testosterone, among the esters synthesized, testosterone propionate was the most potent, and for this reason, was selected for further development, subsequently being marketed. Along with testosterone enanthate, testosterone cypionate, and testosterone undecanoate, Testosterone propionate was introduced in 1937 by Schering AG in Germany under the brand name Testoviron. It was the first ester of testosterone to be introduced, and was the form of testosterone used medically before 1960. In the 1950s, longer-acting testosterone esters like testosterone enanthate and testosterone cypionate were introduced and superseded testosterone propionate, although rarely used nowadays due to its short duration, testosterone propionate remains medically available and is still marketed in the United States. Testosterone acetate Testosterone butyrate Testosterone valerate

15.
International Standard Book Number
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The International Standard Book Number is a unique numeric commercial book identifier. An ISBN is assigned to each edition and variation of a book, for example, an e-book, a paperback and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, the method of assigning an ISBN is nation-based and varies from country to country, often depending on how large the publishing industry is within a country. The initial ISBN configuration of recognition was generated in 1967 based upon the 9-digit Standard Book Numbering created in 1966, the 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108. Occasionally, a book may appear without a printed ISBN if it is printed privately or the author does not follow the usual ISBN procedure, however, this can be rectified later. Another identifier, the International Standard Serial Number, identifies periodical publications such as magazines, the ISBN configuration of recognition was generated in 1967 in the United Kingdom by David Whitaker and in 1968 in the US by Emery Koltay. The 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108, the United Kingdom continued to use the 9-digit SBN code until 1974. The ISO on-line facility only refers back to 1978, an SBN may be converted to an ISBN by prefixing the digit 0. For example, the edition of Mr. J. G. Reeder Returns, published by Hodder in 1965, has SBN340013818 -340 indicating the publisher,01381 their serial number. This can be converted to ISBN 0-340-01381-8, the check digit does not need to be re-calculated, since 1 January 2007, ISBNs have contained 13 digits, a format that is compatible with Bookland European Article Number EAN-13s. An ISBN is assigned to each edition and variation of a book, for example, an ebook, a paperback, and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, a 13-digit ISBN can be separated into its parts, and when this is done it is customary to separate the parts with hyphens or spaces. Separating the parts of a 10-digit ISBN is also done with either hyphens or spaces, figuring out how to correctly separate a given ISBN number is complicated, because most of the parts do not use a fixed number of digits. ISBN issuance is country-specific, in that ISBNs are issued by the ISBN registration agency that is responsible for country or territory regardless of the publication language. Some ISBN registration agencies are based in national libraries or within ministries of culture, in other cases, the ISBN registration service is provided by organisations such as bibliographic data providers that are not government funded. In Canada, ISBNs are issued at no cost with the purpose of encouraging Canadian culture. In the United Kingdom, United States, and some countries, where the service is provided by non-government-funded organisations. Australia, ISBNs are issued by the library services agency Thorpe-Bowker

16.
International Standard Serial Number
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An International Standard Serial Number is an eight-digit serial number used to uniquely identify a serial publication. The ISSN is especially helpful in distinguishing between serials with the same title, ISSN are used in ordering, cataloging, interlibrary loans, and other practices in connection with serial literature. The ISSN system was first drafted as an International Organization for Standardization international standard in 1971, ISO subcommittee TC 46/SC9 is responsible for maintaining the standard. When a serial with the content is published in more than one media type. For example, many serials are published both in print and electronic media, the ISSN system refers to these types as print ISSN and electronic ISSN, respectively. The format of the ISSN is an eight digit code, divided by a hyphen into two four-digit numbers, as an integer number, it can be represented by the first seven digits. The last code digit, which may be 0-9 or an X, is a check digit. Formally, the form of the ISSN code can be expressed as follows, NNNN-NNNC where N is in the set, a digit character. The ISSN of the journal Hearing Research, for example, is 0378-5955, where the final 5 is the check digit, for calculations, an upper case X in the check digit position indicates a check digit of 10. To confirm the check digit, calculate the sum of all eight digits of the ISSN multiplied by its position in the number, the modulus 11 of the sum must be 0. There is an online ISSN checker that can validate an ISSN, ISSN codes are assigned by a network of ISSN National Centres, usually located at national libraries and coordinated by the ISSN International Centre based in Paris. The International Centre is an organization created in 1974 through an agreement between UNESCO and the French government. The International Centre maintains a database of all ISSNs assigned worldwide, at the end of 2016, the ISSN Register contained records for 1,943,572 items. ISSN and ISBN codes are similar in concept, where ISBNs are assigned to individual books, an ISBN might be assigned for particular issues of a serial, in addition to the ISSN code for the serial as a whole. An ISSN, unlike the ISBN code, is an identifier associated with a serial title. For this reason a new ISSN is assigned to a serial each time it undergoes a major title change, separate ISSNs are needed for serials in different media. Thus, the print and electronic versions of a serial need separate ISSNs. Also, a CD-ROM version and a web version of a serial require different ISSNs since two different media are involved, however, the same ISSN can be used for different file formats of the same online serial

17.
PubMed Identifier
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PubMed is a free search engine accessing primarily the MEDLINE database of references and abstracts on life sciences and biomedical topics. The United States National Library of Medicine at the National Institutes of Health maintains the database as part of the Entrez system of information retrieval, from 1971 to 1997, MEDLINE online access to the MEDLARS Online computerized database primarily had been through institutional facilities, such as university libraries. PubMed, first released in January 1996, ushered in the era of private, free, home-, the PubMed system was offered free to the public in June 1997, when MEDLINE searches via the Web were demonstrated, in a ceremony, by Vice President Al Gore. Information about the journals indexed in MEDLINE, and available through PubMed, is found in the NLM Catalog. As of 5 January 2017, PubMed has more than 26.8 million records going back to 1966, selectively to the year 1865, and very selectively to 1809, about 500,000 new records are added each year. As of the date,13.1 million of PubMeds records are listed with their abstracts. In 2016, NLM changed the system so that publishers will be able to directly correct typos. Simple searches on PubMed can be carried out by entering key aspects of a subject into PubMeds search window, when a journal article is indexed, numerous article parameters are extracted and stored as structured information. Such parameters are, Article Type, Secondary identifiers, Language, publication type parameter enables many special features. As these clinical girish can generate small sets of robust studies with considerable precision, since July 2005, the MEDLINE article indexing process extracts important identifiers from the article abstract and puts those in a field called Secondary Identifier. The secondary identifier field is to store numbers to various databases of molecular sequence data, gene expression or chemical compounds. For clinical trials, PubMed extracts trial IDs for the two largest trial registries, ClinicalTrials. gov and the International Standard Randomized Controlled Trial Number Register, a reference which is judged particularly relevant can be marked and related articles can be identified. If relevant, several studies can be selected and related articles to all of them can be generated using the Find related data option, the related articles are then listed in order of relatedness. To create these lists of related articles, PubMed compares words from the title and abstract of each citation, as well as the MeSH headings assigned, using a powerful word-weighted algorithm. The related articles function has been judged to be so precise that some researchers suggest it can be used instead of a full search, a strong feature of PubMed is its ability to automatically link to MeSH terms and subheadings. Examples would be, bad breath links to halitosis, heart attack to myocardial infarction, where appropriate, these MeSH terms are automatically expanded, that is, include more specific terms. Terms like nursing are automatically linked to Nursing or Nursing and this important feature makes PubMed searches automatically more sensitive and avoids false-negative hits by compensating for the diversity of medical terminology. The My NCBI area can be accessed from any computer with web-access, an earlier version of My NCBI was called PubMed Cubby

18.
Androgen receptor
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The androgen receptor is most closely related to the progesterone receptor, and progestins in higher dosages can block the androgen receptor. The main function of the receptor is as a DNA-binding transcription factor that regulates gene expression, however. Androgen regulated genes are critical for the development and maintenance of the male sexual phenotype, hence, testosterone is responsible primarily for the development of male primary sexual characteristics, whereas dihydrotestosterone is responsible for secondary male characteristics. Androgens cause slow epiphysis, or maturation of the bones, steroid users of teen age may find that their growth had been stunted by androgen and/or estrogen excess. People with too little sex hormones can be short during puberty, via the Androgen receptor, androgens play a key role in the maintenance of male skeletal integrity. The regulation of this integrity by androgen receptor signaling can be attributed to both osteoblasts and osteocytes, the primary mechanism of action for androgen receptors is direct regulation of gene transcription. The androgen receptor dimer binds to a sequence of DNA known as a hormone response element. Androgen receptors interact with proteins in the nucleus, resulting in up- or down-regulation of specific gene transcription. Up-regulation or activation of transcription results in increased synthesis of messenger RNA, one of the known target genes of androgen receptor activation is the insulin-like growth factor I receptor. Thus, changes in levels of proteins in cells is one way that androgen receptors control cell behavior. One function of receptor that is independent of direct binding to its target DNA sequence, is facilitated by recruitment via other DNA-binding proteins. One example is serum response factor, a protein that activates several genes that cause muscle growth, AR acetylation is induced by androgens and determines recruitment into chromatin. The AR acetylation site is a key target of NAD-dependent and TSA-dependent histone deacetylases, more recently, androgen receptors have been shown to have a second mode of action. As has been found for other steroid hormone receptors such as estrogen receptors. Androgen receptors interact with certain signal transduction proteins in the cytoplasm, Androgen binding to cytoplasmic androgen receptors can cause rapid changes in cell function independent of changes in gene transcription, such as changes in ion transport. In humans, the receptor is encoded by the AR gene located on the X chromosome at Xq11-12. The androgen insensitivity syndrome, formerly known as testicular feminization, is caused by a mutation of the receptor gene located on the X chromosome. The androgen receptor seems to affect neuron physiology and is defective in Kennedys disease, in addition, point mutations and trinucleotide repeat polymorphisms has been linked to a number of additional disorders

19.
4-Androstenediol
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4-Androstenediol, also known as androst-4-ene-3β, 17β-diol, is an androstenediol that is converted to testosterone. The conversion rate is about 15. 76%, almost triple that of 4-androstenedione, there is also some conversion into estrogen, since testosterone is the metabolic precursor of the estrogens. 4-Androstenediol is closer to testosterone structurally than 5-androstenediol, and has androgenic effects and it has approximately 0. 5% and 0. 6% of the affinity of estradiol at the ERα and ERβ, respectively. Patrick Arnold holds a 1999 patent on Use of 4-androstenediol to increase testosterone levels in humans

20.
5-Androstenedione
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5-Androstenedione is a prohormone of testosterone. The World Anti-Doping Agency prohibits its use in athletes, in the United States, it is a controlled substance. 5-Androstenedione is structurally similar to 4-androstenedione, with the exception of the position of a double bond. 4-Androstenedione is naturally produced in the body by the glands and gonads. In addition to testosterone, it is also a precursor of estrone and estradiol

21.
11-Ketotestosterone
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11-Ketotestosterone is an oxidized form of testosterone that contains a keto group at the C11 position. It is related to adrenosterone, a found in trace quantities in humans. In fish, 11-ketotestosterone functions as the endogenous androgenic sex hormone, in midshipman fish, 11-ketotestosterone is not present in females or Type II Males — Type II Males reach sexual maturation later, are less territorial, and have higher testosterone than Type I Males. In mammals, 11-ketotestosterone has similar potency to testosterone as an androgen and it is synthesized from 11β-hydroxyandrostenedione and, to a lesser extent, 11-ketoandrostenedione. 11-Ketoandrostenedione has notably been sold online as a prohormone, usually under the name 11-oxoandrostenedione

22.
Androstenediol
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Δ5-Diol is a direct metabolite of the most abundant steroid produced by the human adrenal cortex, DHEA. It is less androgenic than the compound, Δ4-androstenediol, and has been found to stimulate the immune system. When administered to rats, Δ5-diol, in vivo, has approximately 1. 4% of the androgenicity of DHEA,0. 54% of the androgenicity of androstenedione, Δ5-Diol possesses potent estrogenic activity, similarly to DHEA and 3β-androstanediol. It has approximately 6% and 17% of the affinity of estradiol at the ERα and ERβ, the value of Δ5-diol as a radiation countermeasure is based mainly on its stimulation of production of white blood cells and platelets. The clinical trials with rhesus monkeys was successful, according to the Hollis-Eden report, only 12. 5% of the 40 Neumune-treated animals died versus 32. 5% in the placebo group. Hollis-Eden had applied for a contract from the U. S. Government under the BioShield Request for Proposals for radiation countermeasures, after being encouraged for 2.5 years that Neumune was in the competitive range, on March 9,2007, the RFP was canceled by HHS. According to HHS, the product was no longer in the competitive range, as a result, Hollis-Eden has now withdrawn from the radiation countermeasure field. 3α-Androstanediol 3β-Androstanediol Regenerative Medicine - Official Hollis-Eden Pharmaceuticals website New Scientist article on AED as an anti-radiation sickness drug

23.
Androstenedione
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In turn, Δ4-dione is also a precursor of dihydrotestosterone, estrogens such as estradiol and estrone, and the neurosteroid 3α-androstanediol. Δ4-Dione is the precursor of the androgen and estrogen sex hormones. Δ4-Dione can be biosynthesized in one of two ways, the primary pathway involves conversion of 17α-hydroxypregnenolone to DHEA by way of 17, 20-lyase, with subsequent conversion of DHEA to Δ4-dione via the enzyme 3β-hydroxysteroid dehydrogenase. The secondary pathway involves conversion of 17α-hydroxyprogesterone, most often a precursor to cortisol, to directly by way of 17. Thus,17, 20-lyase is required for the synthesis of Δ4-dione, Δ4-Dione is produced in the adrenal glands and the gonads. The production of adrenal Δ4-dione is governed by adrenocorticotrophic hormone, whereas production of gonadal Δ4-dione is under control by the gonadotropins, in premenopausal women, the adrenal glands and ovaries each produce about half of the total Δ4-dione. After menopause, Δ4-dione production is about halved, due primarily to the reduction of the steroid secreted by the ovary, nevertheless, Δ4-dione is the principal steroid produced by the postmenopausal ovary. Some Δ4-dione is also secreted into the plasma, and may be converted in peripheral tissues to testosterone, Δ4-Dione is converted to either testosterone or estrogen. In males, conversion of Δ4-dione to testosterone requires the enzyme 17β-hydroxysteroid dehydrogenase, in females, Δ4-dione is released into the blood by theca cells. Conversion of Δ4-dione to estrogen requires the enzyme aromatase, Δ4-Dione is a substrate for estrogen production in granulosa cells which produce aromatase. Thus, theca cells and granulosa cells work together to form estrogens, levels are normally 30-200 ng/dL in females and 40-150 ng/dL in males. Androstanedione is a 5α-reduced metabolite of 4-androstenedione which serves as an intermediate in the biosynthesis of the androgen, Δ4-Dione has been found to possess estrogenic actions, similarly to other DHEA metabolites. However, in contrast to 5-androstenediol, its affinity for the receptors is very low. In juveniles aged 6-8 years old, there is a rise in androstenedione secretion along with DHEA called adrenarche and this rise in androstenedione and DHEA is hypothesized to play a crucial role for learning social, cultural and ecological skills, such as the development and understanding of sexual attraction. Δ4-Dione was manufactured as a supplement, often called andro for short. Sports Illustrated credits Patrick Arnold for introducing Δ4-dione to the North American market, Andro was legal and able to be purchased over the counter, and, as a consequence, it was in common use in Major League Baseball throughout the 1990s by record-breaking sluggers like Mark McGwire. The supplement is banned by the World Anti-Doping Agency, and from the Olympic Games, the International Olympic Committee in 1997 banned Δ4-dione and placed it under the category of androgenic-anabolic steroids. Δ4-Dione is banned by MLB, the NFL, USOC, NCA, barry R. McCaffrey, the director of the White Houses Office of National Drug Control Policy, attempted to determine whether Δ4-dione could be classified as an anabolic steroid in July 1999